CVE-2020-3164

Cisco ESA, Cisco WSA, and Cisco SMA GUI Denial of Service Vulnerability

MEDIUM
5.3
CVSS Score
Published: March 4, 2020 at 06:40 PM UTC
Updated: June 17, 2026 at 03:17 AM UTC
4 products affected across 1 vendorEmail Security ApplianceWeb Security ApplianceContent Security Management Appliance

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Severity
MEDIUM5.3
Exploit prediction
EPSS 1%
SSVC
No known exploit

Description

A vulnerability in the web-based management interface of Cisco AsyncOS for Cisco Email Security Appliance (ESA), Cisco Web Security Appliance (WSA), and Cisco Content Security Management Appliance (SMA) could allow an unauthenticated remote attacker to cause high CPU usage on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific HTTP request headers. An attacker could exploit this vulnerability by sending a malformed HTTP request to an affected device. A successful exploit could allow the attacker to trigger a prolonged status of high CPU utilization relative to the GUI process(es). Upon successful exploitation of this vulnerability, an affected device will still be operative, but its response time and overall performance may be degraded.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 13.0.0-392
v < 13.6.0
Affected range stops below 13.6.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20

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